i

I took the head off for a head-gasket change and cleaning on my 92.... AMC 4.0L HO... there's these little holes in the head where it seemingly has disintegrated, I have no idea what they are, is the head screwed? do i need to buy a replacement or can i just put it back on no worries? thanks for your replies, -Charlie
also, the first bolt on the front of the exhaust manifold broke off inside the head... will i be able to get it out???

 

Those are oil passages, or maybe coolant. The big openings go up to the top, right? Those are for oil to run back down into the block. The smaller ones are coolant, I think. Looks like someone got carried away with sealant, OR, maybe that's just burned old oil. Not good either way. Clean it out!

Other than needing a really good cleaning, I don't see a problem with your head.

 

So that's the thing!! I assumed they were clogged passages but when i hooked my fingernail on one of the chunks in the hole it bent out... its metal!!! i scraped the other spots with a small Flathead and they are solid. I think they might just be dimples from the manufacturing process? im starting to believe my head is done for
thanks for your reply.

 

That's the way they come off you just need to clean it up and clean out the holes , the head gasket will cover the holes that should be covered .

 

Thanks for your reply Tech, I noticed they would be covered by the gasket after posting, but left it up still being unsure if it would affect the integrity of the head.
Now that leaves me with the other issue, i sheared a bolt off of the manifold into the head itself wonder if i can try those "quick out" self tappers to worm it out of there. If i have any luck ill make a post about it.

 

I am not familiar with the head coolant passage layout on XJ, but it does appear that your head casting has "rotted" a hole from the coolant passage

If the reason you were changing the head gasket is that it seemed to be leaking, not just preventative maintenance, then that would be almost for sure

some one with more experience of these heads will chime in shortly

 

if unsure you could always get the head machined ..... I had to do mine last year coolant leak it was worth the $120 aud to get it freshened up

 

If google for pictures of the 4.0 head, they all have those holes. You might just be digging out remnants of the old head gasket and/or gunked oil. If you look at the gasket, you'll see that it covers some of those holes and there are not matching holes in the block.

 

Those tiny triangular holes near the head bolt holes are cooling passages and they are progressive in size as they control how much coolant is allowed to flow between the head and block. In the front of the head, they are small so more hot coolant from the rear of the head is allowed to flow towards the radiator and more cooler coolant from the water pump is directed towards the rear in the block. The holes in the gasket are made the same size so it can be installed either way so some don't go anywhere and are blocked off.

BTW, there are no oil passages in the 4.0 head. All the oil for the valve gear comes up thru the pushrods and is drained back to the pan thru those large holes on the bottom of your second picture.

 

So there I was... standing in the tiny crackerbox garage the Army provided me... dumbfounded.. googling the images of heads.... then i realized! Im actually probably retarted guys. I *never* took the old gasket off. it was metal, and i picked it off with a 000 punch. SHAZAM the head is perfectly fine. thanks for your replies. ive been sulking about my impending roast on this thread all day. thank you for your help guys. WERE ALL GOOD!

 

 

Yeah, don't see that happening.

If anything, there should be some good-natured ribbing about how you posted an image of a cylinder head with a head gasket stuck on it and nobody picked up on it!

How you making out with the broken bolt? Is is rusted in? Loctited in?

 

That bolt hole is drilled thru into the head bolt clearance hole and if the threads weren't sealed on the head bolt when the head was installed, coolant can wick up the threads into that clearance area and rust that stud. It's not your fault it broke if it was rusty, but that's why it's a stud rather than a bolt. Usually the nut comes off before the stud breaks. You should be able to drill it out without worrying you'll break into the water jacket. If the drill goes all the way, you'll see it in the head bolt hole. Don't forget to put thread sealer on that one head bolt when you install the head. It only gets torqued to 100 lb/ft rather than the 105 lb/ft the rest of then are supposed to be because it's threaded into the water jacket and has no bottom in the thread boss, it lacks the metal support the rest of them have. We are talking about the first manifold bolt near the thermostat, right?

Don't feel bad. I think nobody noticed the gasket was still there. I had to go back and look again and yeah, it's still there. D'oh! It seems so obvious now.

 

Havent given it a shot yet, might just take it down to the local shop and have them remove it for me. I could probably get it out myself but im a mix of busy, lazy, and afraid ill break it. if they break the head at least i know it will be replaced